Impression compositions comprising triglycerides

ABSTRACT

The invention relates to impression compositions based on vulcanizable  pother materials, which are characterized in that the ready-mixed pastes comprise 
     a) approx. 30 to 70 wt. % of aziridino-polyether, 
     b) approx. 5 to 20 wt. % of a triacyl glyceride of non-animal origin which has a stearoyl content of ≧70 wt. %, based on the acyl content of the triacyl glyceride, or, in the case of a lower stearoyl content and if this adversely influences the storage stability of the impression composition, has been esterified in itself beforehand, and 
     c) approx. 10 to 65 wt. % of customary catalysts, auxiliaries and additives, 
     in each case based on the total weight of the composition. 
     The impression compositions are distinguished by consistently good mechanical properties of the polymerized materials, have a comparatively low proportion of aziridino-polyether, which has a favourable effect on their preparation costs, and can easily be mixed. During storage of the compositions over long periods of time, no noticeable increase in viscosity occurs, even at elevated temperatures.

The present invention relates to rubber-elastic impression orduplicating compositions which are based on vulcanizable polyethermaterials and are used, in particular, in the dental field, and also inorthopedics. In particular, the present invention describes vulcanizablepolyether pastes with aziridino end groups, addition-crosslinkingpolyether silicone pastes with H--Si groups, and polyether acrylate andmethacrylate pastes which can be vulcanized by free radicals, for theproduction of accurate impressions of jaws with teeth, some teeth or noteeth and of gypsum models.

DE-B-17 45 810 discloses impression compositions of polyether materialswith aziridino end groups. DE-A1-37 41 575 and DE-A1-38 38 587 discloseimpression compositions based on polyether materials with alkenyl groupsand polyorganosiloxane radicals containing H--Si groups, whichpolymerize under the action of platinum catalysts. EP-A2-0 173 085discloses impression compositions of polyether materials with acrylateand methacrylate groups which, after irradiation with light of suitablewavelength, polymerize--under initiation by the dissociation of aphotoinitiator. DE-A1-43 06 997 furthermore discloses impressioncompositions based on polyether materials which are hydrophilized byadditives. These materials have a good capacity for flowing onhydrophilic oral surfaces and therefore have a higher impressionsharpness for these applications than other known impressioncompositions, e.g. based on conventional hydrophobic silicones.

To simplify processing of these impression compositions, thixotropicagents, such as highly disperse fillers, e.g. described in DE-A1-43 21257, or fats of various origins, e.g. described in DE-A1-43 06 997, areadded to them. DE-A1-195 05 896 furthermore describes the addition ofhydrogenated beef tallow to aziridine-free impression materials. It isknown that these thixotropic agents should not exceed a proportion byweight of approx. 10% in polyether materials with aziridino end groups,so that the mechanical properties of the cured impression composition isnot adversely influenced. This means that the proportion ofaziridino-containing polyethers of such impression compositions must liein the range from 50 to 70 per cent by weight, which therefore leadssubstantially to these materials becoming more expensive. Anotherdisadvantage of admixing the thixotropic agents used to date is that theviscosity of polyether pastes comprising such thixotropic agentsincreases constantly in the course of storage, and the usable life ofthese materials is therefore adversely restricted. Pastes without thesethixotropic agents show no tendency to thicken.

The object of the present invention is to provide impressioncompositions which are based on polyethers and comprise thixotropicagents, which can be admixed in amounts of >10 per cent by weightwithout the mechanical properties of the cured compositions beingadversely influenced. Furthermore, the impression compositions preparedwith these thixotropic agents should show the lowest possible increasein viscosity with increasing storage time.

The object is achieved by impression compositions which arecharacterized in that they comprise

a) approx. 30 to 70 wt. % of aziridino-polyether,

b) approx. 5 to 20 wt. % of a triacyl glyceride of non-animal originwhich has a stearoyl content of ≧70 wt. %, based on the acyl content ofthe triacyl glyceride, or, in the case of a lower stearoyl content andif this adversely influences the storage stability of the impressioncomposition, has been esterified in itself beforehand, and

c) approx. 10 to 65 wt. % of customary catalysts, auxiliaries andadditives,

in each case based on the total weight of the ready-mixed composition.

The impression compositions according to the invention preferablycomprise 30 to 40 wt. % of component a), 5 to 20 wt. % of component b)and 40 to 65 wt. % of component c), in each case based on the totalweight of the ready-mixed composition.

Impression compositions of this combination are distinguished, comparedwith the polyether impression materials which are known to date and arebased on aziridine, by consistently good mechanical properties of thecompletely vulcanized and polymerized materials (see examples 1 and 4and table 1), with a significantly lower content of aziridino-polyetherat the same time. As a result, the compositions according to theinvention can be produced considerably less expensively.

In addition, the impression compositions can be mixed more easily by theuse of triacyl glycerides of non-animal origin according to componentb), and therefore allow a shorter production time. Surprisingly, it hasbeen found that by the addition of the triacyl glycerides described, thecompositions according to the invention show no substantial increase inthe viscosity over a period of up to 24 months during storage, even atelevated temperature (examples 1 to 4; and table 1). However, thiseffect can preferably be achieved with those triacyl glycerides ofnon-animal origin in which the stearoyl content is greater than or equalto 70 wt. %, based on the acyl content of the triacyl glyceride. Iftriacyl glycerides in which the stearoyl content is less than 70 wt. %,based on the acyl content of the triacyl glyceride, are used in thecompositions according to the invention, a thickening is sometimesobserved during storage, especially at elevated temperature (comparisonexamples 1 to 4; and table 1). But if such triacyl glycerides arepretreated by interesterification (esterification in themselves), asdescribed in preparation example 2, before being admixed to theimpression composition, the polyether impression compositions producedtherefrom surprisingly show no substantial increase in the viscosityduring storage at elevated temperature (example 2 and table 1). However,triacyl glycerides in which the stearoyl content is <70 wt. % can alsobe employed if the storage stability of the impression composition isnot adversely influenced as a result.

The esterification in the fat itself can be carried out in principle bystirring the fat with a strong base and subsequent neutralization (inthis context, see also "Ullmann's Encyclopaedia of IndustrialChemistry", 5^(th) ed., volume A10, p. 209).

A large number of triacyl glycerides can therefore be used forpreparation of the compositions according to the invention, such as e.g.avocado oil, cottonseed oil, groundnut oil, cacao butter, pumpkin seedoil, linseed oil, maize germ oil, olive oil, palm oil, rice oil,rapeseed oils, safflower oil, sesame oil, soya oil, sunflower oil,grapeseed oil, wheatgerm oil, borneo tallow, fulwa tallow, hemp oil,illipe butter, lupin oil, candlenut oil, kapok oil, katiau fat, kenafseed oil, kekuna oil, poppy oil, mowrah butter, okra oil, perilla oil,sal butter, shea butter and tung oil, if these fats have beenhydrogenated before their use. Hydrogenated fats which are regarded assuitable are those which have an iodine number (measured in accordancewith the standard DGF C-V 11b) of less than 20. Particularly preferredfats are those which have an iodine number of less than 5. Fathydrogenations are carried out, for example, as described in "UllmannsEnzyklopadie der industriellen Chemie [Ullmann's Encyclopaedia ofIndustrial Chemistry]", 4th ed., volume 11, p. 469. Mixtures of thesenaturally occurring fats as well as synthetically produced fats, such ase.g. Softisan 154 or Dynasan 118 (Huls) can also be used. Thepreparation of such synthetic triacyl glycerides is relatively simplefor the expert and can be carried out, for example, from glycerol andthe corresponding fatty acid methyl esters. Such esterificationreactions are described, inter alia, in "Houben-Weyl, Methoden derOrganischen Chemie [Methods of Organic Chemistry]", vol. E5/part 1, p.659 et seq.

Preferred triacyl glycerides correspond to the following formula##STR1## in which R¹, R² and R³ independently of one another denote C₁₁H₂₃ CO, C₁₃ H₂₇ CO, C₁₅ H₃₁ CO or C₁₇ H₃₅ CO, the proportion of C₁₇ H₃₅CO (stearoyl) being ≧70 wt. %, based on the acyl content of the triacylglyceride. Mixtures of such triacyl glycerides are also possible. If theproportion of C₁₇ H₃₅ CO is less than 70 wt. %, the content of thisradical must be distributed randomly over R¹, R² and R³, so that thestorage stability of the impression composition is not adverselyinfluenced. Triacyl glycerides of natural origin which are esterified inthemselves and synthetically prepared triacyl glycerides meet thecondition of random distribution intrinsically.

Polyether materials according to component a) which are suitable for theuse according to the invention are known to the expert. The polyethermaterials described in DE-B-17 45 810 are particularly preferred for thepurpose according to the invention.

Preferred catalysts according to component c) are described in DE-A1-2515 593, and suitable retardants are described in EP-A1-0 110 429. Othersuitable catalysts are e.g. sulphonium salts, for example those whichare described in U.S. Pat. No. 4,167,618. The disclosure content of thepublications mentioned which is referred to is to be expressly includedhere.

Customary auxiliaries and additives according to component c) arestabilizers, plasticizers, pigments and fillers. Examples of suchauxiliaries and additives are described, inter alia, in DE-A-17 48 510.

To prevent premature curing of the impression compositions, thepolyether materials on the one hand and the catalysts on the other handmust be kept separate from one another until used. Preferably, the twocomponents are present in the form of pastes. In a preferred embodiment,the base components and the catalyst are present in paste form andspatially separate from one another, the base component comprising i) 30to 75 wt. % aziridino-polyether, ii) 5 to 25 wt. % of a triacylglyceride of non-animal origin which has a stearoyl content of ≧70 wt.%, based on the acyl content of the triacyl glyceride, or, in the caseof a lower stearoyl content and if this adversely influences the storagestability of the impression composition, has been esterified in itselfbeforehand, and iii) 0 to 65 wt. % of customary auxiliaries andadditives, and the catalyst component comprising iv) 10 to 60 wt. % of acustomary catalyst, v) 0 to 25 wt. % of a triacyl glyceride according tocomponent ii) and vi) 15 to 90 wt. % of customary auxiliaries andadditives, the wt. % data in each case being based on the total weightof the base paste and catalyst paste respectively.

To improve the mixing properties with the polymerization catalyst of theother paste, which catalyst is dissolved in the solvent or plasticizeror kept in suspension by means of suspending agents or kept in emulsionby means of emulsifiers, the vulcanizable polyether materials of the onepaste can comprise the same or chemically similar plasticizers orsolvents.

The use of solutions of the crosslinking agent in suitable plasticizers,solvents or plasticizer mixtures is expedient; in this manner, not onlyare extreme mixing ratios avoided, but solid initiators are alsodissolved.

Customary plasticizers are often readily compatible with the polyethermaterials. Their use is advisable not only for economic reasons, butalso to improve the properties, in particular to avoid or reducecrystallization. Plasticizers which are suitable are, for example,phthalic acid esters, glycol derivatives and polymeric plasticizers,sorbitan esters etc. Customary and suitable plasticizers are described,for example, in Polyethers, part I, edited by Norman G. Gaylord,Interscience Publishers (1963). The properties of the end products canbe varied widely by the choice of a suitable starting material, so thatthe mechanical values of the end products can be established virtuallyas required. Nevertheless, the addition of relatively large amounts ofplasticizer and/or other customary additives can influence theabsorption of water, swelling and change in dimensions to a degree suchthat the impression cannot be used.

EXAMPLES Preparation Example 1 (Preparation of a Catalyst Paste)

32.7 g of a sulphonium salt which has been obtained according to example27 of DE-A1-25 15 593, 32.2 g acetyl-tributyl citrate, 5.8 g of a blockcopolymer surfactant of propylene oxide and ethylene oxide having anaverage molecular weight of 6,500, 19.1 g pyrogenic silicic acid, 9.5 gkieselguhr and 0.7 g pigments are kneaded to give a total of 100 g of apaste. This is used as paste B in the following examples.

Comparison Example 1

57.9 g of an aziridino-polyether which has been obtained according toexample 12 of DE-B 17 45 810 are mixed with 11.6 g dibenzyltoluene, 11.6g hydrogenated palm oil and 16.3 g kieselguhr. After addition of 2.6 gof a mixture of retardant, coloured pigment and aroma, 100 g of a pasteVA1 are obtained.

Base paste VA1 and catalyst paste B are mixed completely with oneanother in a weight ratio of 1,000 g VA1:140 g B. After some minutes, arubber-elastic composition is obtained.

On the resulting cured composition, the permanent deformation ofrecovery after deformation of 1.4% and the deformation under pressure of2.35% are measured in accordance with ISO 4823 (see also table 1).

Paste VA1 is stored at a constant temperature of 50° C. After periodicintervals, the viscosity is measured with a Haake viscometer. Theviscosity exceeds 1,300 Pa.s after only one week (table 1).

Example 1

39.6 g of an aziridino-polyether which has been obtained according toexample 12 of DE-B 17 45 810 are mixed with 23 g dibenzyltoluene, 17 ghydrogenated soya oil, 0.5 g of a block copolymer surfactant ofpropylene oxide and ethylene oxide having an average molecular weight of4,400 and 17.8 g kieselguhr. After addition 2.1 g of a mixture ofretardant, colored pigment and aroma, 100 g of a paste A1 are obtained.

Base paste A1 and catalyst paste B are mixed completely with one anotherin a weight ratio of 1,000 g A1:100 g B. After some minutes, arubber-elastic composition is obtained.

On the resulting cured composition, the permanent deformation ofrecovery after deformation of 1.35% and the deformation under pressureof 2.65% are measured in accordance with ISO 4823 (see also table 1).

Paste A1 is stored at a constant temperature of 50° C. After periodicintervals, the viscosity is measured with a Haake viscometer. Even aftertwo years, the viscosity remains below 1,000 Pa.s (table 1).

Comparison Example 2

39.6 g of an aziridino-polyether which has been obtained according toexample 12 of DE-B 17 45 810 are mixed with 21.6 g dibenzyltoluene, 9.8g hydrogenated beef tallow, 3.7 g of a block copolymer surfactant ofpropylene oxide and ethylene oxide having an average molecular weight of4,400 and 23.6 g kieselguhr. After addition of 1.7 g of a mixture ofretardant, coloured pigment and aroma, 100 g of a paste VA2 areobtained.

Base paste VA2 and catalyst paste B are mixed completely with oneanother in a weight ratio of 1,000 g VA2:100 g B. After some minutes, arubber-elastic composition is obtained. On the resulting curedcomposition, the permanent deformation of recovery after deformation of2.3% and the deformation under pressure of 3.9% are measured inaccordance with ISO 4823 (see also table 1).

Paste VA2 is stored at a constant temperature of 50° C. After periodicintervals, the viscosity is measured with a Haake viscometer. Theviscosity exceeds 1,300 Pa.s after only two weeks (table 1).

Preparation Example 2 (Esterification of a Fat in Itself)

100 g hydrogenated palm oil (e.g. PRIFAT 9835 from Unichema) are meltedat 80° C., and 1.0 wt. % sodium methylate is added. The reaction mixtureis stirred at 80° C. in vacuo for one hour and is then taken up in 300ml toluene and extracted by shaking in each case once with dilute aceticacid and once with deionized water. After drying over sodium sulphate,the solvent is removed in vacuo and 97 g of palm oil esterified initself are obtained.

Example 2

57.9 g of an aziridino-polyether which has been obtained according toexample 12 of DE-B 17 45 810 are mixed with 11.6 g dibenzyltoluene, 11.6g palm oil transesterified according to preparation example 2 (seeabove) and 16.3 g kieselguhr. After addition of 2.6 g of a mixture ofretardant, coloured pigment and aroma, 100 g of a paste A2 are obtained.

Base paste A2 and catalyst paste B are mixed completely with one anotherin a weight ratio of 1,000 g A2:140 g B. After some minutes arubber-elastic composition is obtained.

On the resulting cured composition, the permanent deformation ofrecovery after deformation of 1.25% and the deformation under pressureof 2.6% are measured in accordance with ISO 4823 (see also table 1).

Paste A2 is stored at a constant temperature of 50° C. After periodicintervals, the viscosity is measured with a Haake viscometer. Even aftertwo years, the viscosity remains below 1,000 Pa.s (table 1).

Example 3

57.9 g of an aziridino-polyether which has been obtained according toexample 12 of DE-B 17 45 810 are mixed with 11.6 g dibenzyltoluene, 11.6g synthetic triacyl glyceride (SOFTISAN 154 Huls) and 16.3 g kieselguhr.After addition of 2.6 g of a mixture of retardant, coloured pigment andaroma, 100 g of a paste A3 are obtained.

Base paste A3 and catalyst paste B are mixed completely with one anotherin a weight ratio of 1,000 g A3:140 g B. After some minutes, arubber-elastic composition is obtained.

On the resulting cured composition, the permanent deformation ofrecovery after deformation of 1.5% and the deformation under pressure of2.15% are measured in accordance with ISO 4823 (see also table 1).

Paste A3 is stored at a constant temperature of 50° C. After periodicintervals, the viscosity is measured with a Haake viscometer. Even aftertwo years, the viscosity remains below 1,000 Pa.s (table 1).

Comparison Example 3

57.9 g of an aziridino-polyether which has been obtained according toexample 12 of DE-B 17 45 810 are mixed with 11.6 g dibenzyltoluene, 11.6g Dynasan P60 (Huls) and 16.3 g kieselguhr. After addition of 2.6 g of amixture of retardant, coloured pigment and aroma, 100 g of a paste VA3are obtained.

Base paste VA3 and catalyst paste B are mixed completely with oneanother in a weight ratio of 1,000 g VA3:140 g B. After some minutes, arubber-elastic composition is obtained.

On the resulting cured composition, the permanent deformation ofrecovery after deformation of 1.8% and the deformation under pressure of3.25% are measured in accordance with ISO 4823 (see also table 1).

Paste VA3 is stored at a constant temperature of 50° C. After periodicintervals, the viscosity is measured with a Haake viscometer. Theviscosity exceeds 1,300 Pa.s after only one week (table 1).

Comparison Example 4

57.9 g of an aziridino-polyether which has been obtained according toexample 12 of DE-B 17 45 810 are mixed with 11.6 g dibenzyltoluene, 11.6g hydrogenated beef tallow and 16.3 g kieselguhr. After addition of 2.6g of a mixture of retardant, coloured pigment and aroma, 100 g of apaste VA4 are obtained.

Base paste VA4 and catalyst paste B are mixed completely with oneanother in a weight ratio of 1,000 g VA4:140 g B. After some minutes, arubber-elastic composition is obtained.

On the resulting cured composition, the permanent deformation ofrecovery after deformation of 1.8% and the deformation under pressure of2.6% are measured in accordance with ISO 4823 (see also table 1).

Paste VA4 is stored at a constant temperature of 50° C. After periodicintervals, the viscosity is measured with a Haake viscometer. Theviscosity exceeds 1,300 Pa.s after only two weeks (table 1).

Example 4

39.6 g of an aziridino-polyether which has been obtained according toexample 12 of DE-B 17 45 810 are mixed with 21.6 g dibenzyltoluene, 9.8g hydrogenated soya oil, 3.7 g of a block copolymer surfactant ofpropylene oxide and ethylene oxide having an average molecular weight of4,400 and 23.6 g kieselguhr. After addition of 1.7 g of a mixture ofretardant, coloured pigment and aroma, 100 g of a paste A4 are obtained.

Base paste A4 and catalyst paste B are mixed completely with one anotherin a weight ratio of 1,000 g A4:100 g B. After some minutes, arubber-elastic composition is obtained.

On the resulting cured composition, the permanent deformation ofrecovery after deformation of 1.4% and the deformation under pressure of2.7% are measured in accordance with ISO 4823 (see also table 1).

Paste A4 is stored at a constant temperature of 50° C. After periodicintervals, the viscosity is measured with a Haake viscometer. Even aftertwo years, the viscosity remains below 1,000 Pa.s (table 1).

Each of the publications referred to above is hereby incorporated byreference.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

                                      TABLE 1                                     __________________________________________________________________________    Mechanical properties and viscosity storage data of the polyether pastes                    Comparison  Comparison       Comparison                                                                           Comparison                     example Example example Example Example example example Example                                                                     Example no.: 1 1                                                             2 2 3 3 4             __________________________________________________________________________                                                            4                     Base paste comprises                                                                        hyd. palm oil                                                                        hyd. soya                                                                          beef tallow                                                                          transest.                                                                          Softisan                                                                           Dynasan P 60                                                                         beef tallow                                                                         hyd. soya oil                                                                    oil  palm oil                                                               Aziridino-polyeth                                                            er 57.9 39.6 39.6                                                             57.9 57.9 57.9                                                                57.9 39.6                                                                      [wt. %}                Thixotropic agent 11.6 17 9.8 11.6 11.6 11.6 11.6 9.8                         [wt. %]                                                                       Base:Cat. 7:1 10:1 10:1 7:1 7:1 7:1 7:1 10:1                                  PE content in the mixture 50.79 36 36 50.79 50.79 50.79 50.79 36                                                                     [wt. %]                Thixotropic agent content in 10.2 15.5 8.9 10.2 10.2 10.2 10.2 8.9                                                                   the mixture                                                                   [wt.]                  Mech. properties + + -- + + -- + +                                            Permanent deformation 1.4 1.35 2.3 1.25 1.5 1.8 1.8 1.4                       [%]                                                                           Elastic deformation 2.35 2.65 3.9 2.6 2.15 3.25 2.6 2.7                       [%]                                                                           Storage stability + -- + + -- -- +                                            (50° C.)                                                               Time to viscosity > 1,300 Pa · s 1 week 2 years 2 weeks 2                                                                  years 2 years 1                                                               week 2 weeks 2                                                                years                     stable  stable stable   stable                                            __________________________________________________________________________

We claim:
 1. A ready-mixed impression composition based on vulcanizablepolyether materials comprising(a) about 30 to 70 wt. % ofaziridino-polyether, and (b) about 5 to 20 wt. % of a triacyl glycerideof non-animal origin which (1) has a stearoyl content of ≧70 wt. %,based on the acyl content of the triacyl glyceride; or (2) has astearoyl content of <70 wt. % and has been interesterified to avoidadverse influences on the storage stability of the impressioncomposition; wherein the wt. % of (a) and (b) are based on the totalweight of the composition.
 2. The impression composition according toclaim 1, which further comprises (c) about 10 to 65 wt. % of customarycatalysts, auxiliaries or additives.
 3. The impression compositionaccording to claim 1, wherein component b) comprises a mixture oftriacyl glycerides.
 4. The impression composition according to claim 1,wherein component b) is a synthetic triacyl glyceride.
 5. The impressioncomposition according to claim 1, wherein the triacyl glyceride has thefollowing formula ##STR2## in which R¹, R² and R³ independently of oneanother have the meaning C₁₁ H₂₃ CO, C₁₃ H₂₇ CO, C₁₅ H₃₁ CO or C₁₇ H₃₅CO, the proportion of C₁₇ H₃₅ CO being ≧70 wt. %, based on the acylcontent of the triacyl glyceride, or if the proportion of C₁₇ H₃₅ CO islower, this being distributed randomly among the radicals R¹, R² and R³.6. The impression composition according to claim 2, which comprises 30to 40 wt. % of component (a), 5 to 20 wt. % of component (b), and 40 to65 wt. % of component (c).
 7. A ready-mixed impression composition basedon vulcanizable polyether materials comprising, base components and acatalyst which are present in paste form spatially separate from oneanother, the base component comprising i) 30 to 75 wt. %aziridino-polyether, ii) 5 to 25 wt. % of a triacyl glyceride, and iii)0 to 65 wt. % of customary auxiliaries and additives, and the catalystcomponent comprising iv) 10 to 60 wt. % of a customary catalyst, v) 0 to25 wt. % of a triacyl glyceride according to component ii and vi) 15 to90 wt. % of customary auxiliaries and additives, the wt. % data in eachcase being based on the total weight of the base paste and catalystpaste respectively.
 8. A method of using triacyl glyceride to increasethe storage time of a polyether-containing vulcanizable impressionmaterial, which comprises mixing an aziridino-polyether with a triacylglyceride of non-animal origin which (a) has a stearoyl content of ≧70wt. %, based on the acyl content of the triacyl glyceride, or (b) has astearoyl content of <70 wt. % and has been interesterified to avoidadverse influences on the storage stability of the impressioncomposition.
 9. The ready-mixed impression composition according toclaim 1, wherein triacyl glyceride (2) has a random distribution ofstearoyl groups on the triacyl glyceride.
 10. The method according toclaim 8, wherein triacyl glyceride (b) has a random distribution ofstearoyl groups on the triacyl glyceride.
 11. The ready-mixed impressioncomposition according to claim 1, wherein the triacyl glyceride ishydrogenated and is selected from the group consisting of avocado oil,cottonseed, oil, groundnut oil, cacao butter, pumpkin seed oil, linseedoil, maize germ oil, olive oil, palm oil, rice oil, rapeseed oils,safflower oil, sesame oil, soya oil, sunflower oil, grapeseed oil,wheatgerm oil, borneo tallow, fulwa tallow, hemp oil, illipe butter,lupin oil, candlenut oil, kapok oil, katiau fat, kenaf seed oil, kekunaoil, poppy oil, mowrah butter, okra oil, perilla oil, sal butter, sheabutter and tung oil.
 12. The method according to claim 8, wherein thetriacyl glyceride is hydrogenated and is selected from the groupconsisting of avocado oil, cottonseed, oil, groundnut oil, cacao butter,pumpkin seed oil, linseed oil, maize germ oil, olive oil, palm oil, riceoil, rapeseed oils, safflower oil, sesame oil, soya oil, sunflower oil,grapeseed oil, wheatgerm oil, borneo tallow, fulwa tallow, hemp oil,illipe butter, lupin oil, candlenut oil, kapok oil, katiau fat, kenafseed oil, kekuna oil, poppy oil, mowrah butter, okra oil, perilla oil,sal butter, shea butter and tung oil.
 13. The ready-mixed impressioncomposition according to claim 1, wherein the triacyl glyceride has aniodine number of less than
 20. 14. The method according to claim 8,wherein the triacyl glyceride has an iodine number of less than
 20. 15.The ready-mixed impression composition according to claim 1, wherein thetriacyl glyceride (2) is synthetic.
 16. The method according to claim 8,wherein the triacyl glyceride (b) is synthetic.